Cohort Profile: The Central Denmark Cancer Cohort

Cancer outcome studies frequently utilize registry data, which provide large-scale population-level information. However, these registries often lack detailed clinical information regarding comorbidities, lifestyle factors, and in-hospital treatments. The Central Denmark Cancer Cohort (CDCC) was established to address these limitations by linking medical and administrative registry data with clinical electronic medical records (EMR), to facilitate research to better understand the clinical course of cancer and its complications.

The CDCC includes all patients with incident cancer, except non-melanoma skin cancer, diagnosed in the Central Denmark Region between 2012 and 2021, with complete follow-up through December 31, 2021. The CDCC was identified from the Danish Cancer Registry and linked via the Civil Personal Registration number to the Central Denmark Region Clinical Information System (CDRCIS) and to national registries, including the Danish National Patient Registry, National Prescription Registry, and Register of Laboratory Results for Research. We extracted data on demographics, lifestyle factors, comorbidities, treatments, and survival outcomes and assessed the availability of these data.

The CDCC included 68,028 patients with a median age of 68 years (interquartile range: 59-76 years); 47.2% were female. The most common cancers were prostate cancer (10,024 patients), breast cancer (9,100 patients), and non-small cell lung carcinoma (7,264 patients). At diagnosis, 98.0% of patients had laboratory test results available, 87.5% received at least one in-hospital medication, and 86.9% had at least one characteristic documented in CDRCIS. During median follow-up of 2.6 years, 37.8% of patients died and five-year survival was 59.0% (95% confidence interval: 58.6-59.4%). Data completeness varied by cancer type.

The CDCC integrates clinical, lifestyle, and laboratory data with cancer registry information. By capturing factors typically unavailable in registry-based research, this platform offers a unique foundation for longitudinal studies on the clinical course of cancer.